Today I got around to mounting the HID ballast onto the left wing. I mounted everything on the outboard end rib.
I fabbed a bracket for the transformer out of 0.025. The bracket is a single piece riveted to the rib and the retainer strap is screwed down to hold the transformer in place. I lined the braked with foam tape as a cushion. The bracket also has a lip at either end preventing the transformer from sliding out, ever if the clamping force doesn't hold it.
The ballast is attached with three #6 screws and nutplates.
Ignore the cushion clamp and hardware. That clamp is too small and the hardware is wrong. I just bolted it up to see how everything would come together.
HID mounted to outboard rib. The hardware and clamp is temp - will be replaced.